I. Field of the Invention
The present invention relates to wireless communication devices and production testing thereof. More particularly, the present invention relates to a novel and improved dual purpose connection for a wireless communication device which interfaces with an antenna in normal use and interfaces with a connector interface during production testing.
II. Description of the Related Art
Wireless communication devices are becoming increasingly prevalent, with cellular telephones being a particularly notable example. With these devices, radio-frequency (RF) signals are transmitted and received to create a communication link to the device. During the manufacture of such devices, it is necessary to functionally test the RF signal generation and reception circuitry as well as the signal processing circuitry prior to shipment of the device to a customer.
The typical testing procedure for such devices includes placing a small test antenna near the antenna installed on the wireless communication device. Test signals are passed between the two antennas to test sensitivity, output power, and other parameters of the RF circuitry and signal processing circuitry of the device. One such wireless communication device is a portable cellular telephone. A single cellular telephone may have two antennas each of which may be used to transmit and receive RF signals. These two antennas are typically embodied in a single antenna assembly such as a retractable monopole whip antenna for normal RF transmission and a small helical antenna which remains external to the telephone body, even when the monopole whip antenna is retracted within the telephone body. Either the monopole whip antenna or the helical antenna may be used to transfer RF signals during normal operation. An example of such a system is disclosed in U.S. Pat. No. 5,353,036 to Baldry. In addition, the helical antenna may be used for transmitting and receiving signals to and from a test antenna. Although acceptably precise measurements of cellular telephone performance characteristics can be made with this system under some conditions, it is difficult to prevent the accumulation of small errors in the manufacturing environment which degrade the quality of the results obtained. Furthermore, in the manufacturing environment, where many devices may be tested simultaneously, interference from neighboring RF sources can affect measurement accuracy.
In spite of the drawbacks of testing by the coupling of two antennas, wireless communication devices have not generally included suitable interface hardware for testing which does not rely on such coupling. In U.S. Pat. No. 5,394,162 to Korovesis, et al., these problems are considered in conjunction with the testing of cellular telephones mounted inside vehicles. In this case, the whip antenna is usually provided on an exterior surface of the vehicle, such as the rear window, to transfer the RF signals outside of the vehicle itself. In particular, Korovesis et al. describe an RF coupler with a ground plane having a hole in its center which is placed over the whip antenna interface on the rear window prior to installation of the whip. A semicircular contact is placed in electrical contact with the antenna interface base. Although this apparatus allows telephone testing without using the antenna, interference can still be a problem. To help minimize such interference, a mesh EMI shield is preferably placed over the test apparatus during use. The present invention is substantially less cumbersome compared to such an arrangement.
Thus, it will be appreciated that there is a need in the technology for a means and method for providing a connection between a wireless device under test and standard test equipment which overcomes the cumbersome nature of the prior art and which eliminates the need for radiated fields. The present invention provides a direct and efficient connection which is suitable for the production environment and which does not require an additional port on the device.